Light responsive sign



Aug. 3, 1965 M. M. BUZAN LIGHT RESPONSIVE SIGN 2 Sheets-Sheet 1 Filed Aug. 22, 1962 FlG.l.

INVENTOR. MORRIS M. BUZAN ATTORNEYS Aug. 3, 1965 M. M. BUZAN 3,197,902

LIGHT RESPONSIVE SIGN Filed Aug. 22, 1962 2 Sheets-Sheet 2 INVENTOR. MORRIS M. BUZAN ATTORNEYS M M 4 111 ll. I 3

I l I l I I l I I I I II r U i? United States Patent 3,197,902 LIGHT RESPONSIVE SIGN Morris M. Buzan, St. Louis County, Mo.,' assignor, by

mesne assignments, to Emerson Electric Co., a corporation of Missouri Filed Aug. 22, 1962, Ser. No. 218,670 2 Claims. (01. 40-430 This invention relates to light responsive signs and is especially useful in public buildings where the public are expected to gather during day or night activity.

Most signs are usually made visible by response to either internal or external illumination, and with the proper application of light, visibility is made easy. However, such signs cannot or do not have equal visibility under the reserve condition. That is to say, internally illuminated signs do not have good visibility under high external illumination, nor do externally illuminated signs have good visibility under low external illumination. While internal illumination is most used, the problem is to provide an internally illuminated sign which has approximately equal visibility in both high and low ambient light levels (i.e. light or dark).

In addition to the foregoing problem which this invention has solved, it is desirable to make the sign as compact and thin as possible to match the trends in architectural design of building components for surface mounting rather than for recessed mounting. Obviously, a recessed type component or sign may be quite thick as only the face portion needs to be seen, but with the entire body in a position to be seen the thickness characteristic must be regulated in order to have an attractive and saleable product. A thin body makes the problem of sign visibility much more difficult in the case of a trans-illuminatedsign. If a proper relationship between the lamps and the sign face cannot be maintained, then the resultant bright and dark areas tend to reduce visibility. Obtaining a sign compatible with both high and low external light levels is still more difficult.

It is an object of this invention to provide an internally illuminated sign which is thin and also responsive to ambient natural or artificial light so that visibility in the daytime and at night is assured, as well as visibility in going quickly from a darkened room to a lighted one.

It is an object of this invention to provide a sign having the foregoing characteristics with an improved light re- "ice ings in certain preferred forms, wherein:

FIG. 1 is a front view of a preferred sign arranged to be mounted from its upper margin;

FIG. 2 is a greatly enlarged transversesectional elevational view taken at line 2-2 in FIG. 1;

sponsive face for displaying the legend, information, di-

with an increase in external illumination by providing a sign which will acquire greater visibility.

It is another object of this invention to provide a sign internally illuminated by low wattage lamps so that it is effectively visible with a minimum of power consumed, and may be continuously energized Without expenditure of excessive electrical current.

A preferred sign having theforegoing broad characteristics includes a compact, thin-section frame for a clear plastic face with the lettering for the sign applied to the back surface. The sign face is illuminated by electric lamps from an edge and very little light energy is lost due to its manner of containment within the face for purposes of illuminating the letters. The light energy within the face is bounced about within the thickness of the same and in front of the legend and produces the visibility and contrast with a backing means forthe letters, the object being, to minimize light loss through the letters or through the backing when the legend is sten- FIG. 3 is an exploded perspective view of certain important components of the sign of FIG. 1;

FIG. 4 is a plan view of a sign component in which the electrical lamps are secured in a body of insulating maten'al for convenient mounting as shown in FIGS. 2 and 3; r

FIG. 5 is a perspective view of the sign face as viewed from the rear surface, showing one form of legend in the form of applied letters;

FIG. 6 is a greatly enlarged transverse sectional elevational view of a modification of the sign shown in FIG. 2; and

FIG. 7 is a modification of the sign face to show a stenoil-like legend with the reflective coating surrounding the openings which obtain their optical contrast by showing the surfaces of the backing means used behind the face.

The embodiment of this invention shown in FIGS. 1 to 4 inclusive is particularly designed as an EXIT sign for public or commercial building usage. The sign 19 consists in a frame 11 of shallow dished form having a back 12, and flange 13 or four sides defining an open front. A liner 14 is located in the frame and the sign face 15 is carried by the liner in position to be enclosed bya rim 16. The assembled sign is supported by a mounting bracket 17 which is disposed along the top margin (FIG. 1) but may be disposed at either end or adjacent the back, depending on the place for making the required electrical connections or the manner of erecting the sign to harmonize with surroundings.

In FIGS. 2, 3 and 5, the face 15 is a panel made from a body of transparent, colorless plastic material (methyl methacrylate is preferred) and is polished on edges 18, IQ and 20. A specular reflecting material is applied to each of these edges, and is in the form of tape T (FIG. 5). In the place of tape a metallic coating sprayed or vaporized directly to the edges may be used. The tape T or its equivalent specular material provides a highly efficient light reflecting surface for light travelling in the face 15. The edge 21 is either polished or roughened to provide for a degree of diffusion of light entering at that edge, or a degree of diffusion.

The rear surface of face 15 (FIG. 5 is used to support the sign letters L-l, L-Z, L-3 and L4, although of course, the specific number of letters are not important as this is a variable of any sign.

Each letter is formed by the use of a high reflectance paint P applied to the rear surface of the face 15, and for this purpose a daylight type .paint using fluorescent pigments has the required degree of visibility, and either orange-red or green color is prefer-red. The daylight fluorescent pigment is capable of converting light in other wave lengths to the wave length of the pigment color. That is to say, using the orange-red paint, ultraviolet energy and visible light in the red-orange band reinforces the red-orange light which is available and increases the apparent brightness of the paint. The letters L1, L-2, L-S and L are preferably applied by the well known silk screen process, although the letters may be applied by stencilling methods or by masking the surfaces which are not to be painted. Each letter is given an opaque coating, such as by the application of flat white paint, so that transparency of the fluorescent paint is overcome and very little light loss is experienced with the result that the letters are materially increased in ability to reflect light. It is understood in connection with FIGS. 3 and 5 that the letters which make up the EXIT sign are composed of the foregoing described layer of fluorescent pigment and a backing layer of an opaque material. These letters are said to be in optical contact with the face 15.

In FIGS. 2 and 3 it is seen that the liner 14 consists in suitable material having the flat surface 22 bounded on its bottom margin by a channel shaped flange 23 and on each of its two opposite ends with short channel flanges 24 and 25. At either end of the channels 24 and 25 there are. provided ears 26 and 27 which are reversely turned or bent backwardly relative to the surface 22. The ears 26 and 27 serve to locate the surface 22 of liner 14 at the proper depth within the frame 11 (FIG. 2.) 'Prior to disposing the liner 14 Within the frame 11 the face 15 is slidably mounted in the channels 24 and 25 with its lower edge 20 seated in the channel 23. This leaves the edge 21 of the face 15 unobstructed throughout its full length for a purpose to appear.

The liner 14 has its surface 22 treated with a coating, preferably bright chrome-aluminum paint, for the purpose of increasing contrast between the fluorescent pigment in the letters and the exposed surface 22 of the liner. The liner 14 is not necessarily in optical contact with the face 15, and its surface 22 may be separate and carried by the face 15 rather than as a coated surface on liner 14.

As may be seen in FIGS. 2 and 4, the sign is provided with a row of electric lamps 28 which are embedded in a suitable body 29 of material such as thermo setting plastic selected from a castable polyester resin, or an expoxy cast resin. The resin may either be opaque or transparent, although it is preferred that it be a white pigment opaque material. As viewed in FIG. 4 each lamp 28 has a portion of its body exposed for the emission of light rays. This condition would prevail when using the opaque embedding compound, whereas, the use of a transparent clear material would allow complete encapsulation. The lamps are suitably provided with leads which are connected in parallel with the electric current leads 3t) and 31. The thus formed series of lamps 28 are suitably mounted by means of screws 32 to the upper portion of the frame flange 13 (see FIG. 3) at a position such that the lamps 28 are aligned with the edge 21 of the face '15. The proper alignment between the lamps 28 and the edge 21 may be determined by the length of the locating ears 26 and 27 onthe liner 14. There is a space enclosed between the back of the liner surface 22 and the back 12 of the frame 11 which can provide a suitable cavity for the mounting of a transformer 33. (The necessity for the transformer will be explained later.) The leads .30 and 3 1 from the body of castable material 29 retaining the lamps 28 in position are combined in an insulated. cord 34 which is connected with the one side of the transformer 33, the opposite cord 35 from the transformer leads from the frame 11 through the mounting bracket 17 to a convenient source of electrical current. 2

After the face 15 has been mounted in the liner 14, and the two parts disposed within the frame 11 the rim 16 may be assembled by first inserting one or more prongs 36 along the upper horizontal flange 37 into one or more slots formed in the upper portion of the frame flange 13. The lower margin 37 of the rim 16 is provided with an indented portion 38 which snap fits into configuration to provide a pleasing appearance for the letters on the face 15 of the assembled sign.

In FIG. 6 a modification of the present invention is illustrated in the form of a double faced sign, the components of which are substantially identical with the correspending components of the single faced sign shown in FIG. 2. The difference consists primarily in that there is a hoop type frame 41 in place of the frame 11, and the left hand sign face 15' is mounted in a liner 14' which is suitably modified with a lower flange 42 and an upper flange 43, which have a sliding fit in the frame 4 1. The liner 1- 1 thereby acts as a locating member for the liner 14 supporting the right hand sign face 15 on which the ears 26 and 27 are provided. The modified frame 41 supports a pair of bodies 29 of the type shown in FIG. 4. Since there are two series of lamps 28, each series has its own transformer 33 with suitable electrical current connections 34, and 35 for the right hand sign face '15 and connections 44 and 45 for the left hand sign face 15. Each sign face 15 is enclosed by a rim 16 mounted as heretofore described in connection with FIG. 2.

In a sign of the herein described character it may now be appreciated that once light from the series of lamps 23 enters within the body of the face 15, the polished parallel edge surfaces will cause the light to inter-reflect and bounce around throughout the face. A certain amount of light energy can be expected to be lost, however, this light loss is reduced to a minimum by treating the edges 18, 1 and 20 with a heretofore described specular reflecting material, applied either as a tape material T, or as a metallic coating. In order to obtain the optimum degree of light distribution through out the body of the face 15 it has been determined that the body of the face of about 7" x 11" should be approximately A of an inch thick, for signs having approximately this area and amount of internal illumination. If either of these variables change, a different face thickness may be required.

The lettering carried on the face 15 is preferably placed on the back side thereof to avoid the development of silhouette type letters. By locating the letters at the rear surface, the light energy travelling in the body of the face 15 is better able 'to evenly distribute itself so as to illuminate substantially all of the letters evenly and the letters reflect the light energy in the direction of viewing of the sign. The light reflectance developed in the letters of the sign provides a sharp contrast with the treatment of the surface 22 of the liner 14. When the sign is located in a darkened room with the lamps 28 energized, the letters are illuminated and are seen against a dark background. When the fixture is exposed to ambient: light the reflexivity or light responsiveness of the background surface 22 causes it to appear much brighter than the letters and the letters are more easily seen because of the relative shift in the contrast between the letters and the liner surface 22.

In a room lighted by daylight or electric light the light energy enters from the front surface of the face 15 and is reflected back by the fluorescent material from the letters. Since the letters are of fluorescent paint and the liner surface 22 is treated with a bright chromealuminum paint, the contrast is quite apparent so that the sign may be easily read from a considerable distance.

a corresponding recess 39 in the lower portion of the 7 frame flange '13. In this way, the rim 16 may be pivoted from the elements 36 into or out of assembled position. The rim is. provided with a border flange 40 of tapered The lamps 28 are by preference miniature incandescent lamps; most types of which require a relatively low voltage. This voltage can be supplied by means of a transformer 33 which has been located within the body of the sign, although the transformer 33 could be located within the mounting bracket 17 or a more remote location. This would allow a sign of still thinner design.

Because of the low light output required for visibility of the legend or sign wording, the voltage to the lamps 28 (i.e. transformer output voltage) can be selected so that a relatively long lamp life can be expected with a minimum of power consumption.

As seen in FIG. 7, the modified sign face 15' has the legend or letters L 1 L-Z, L-S' and L-4' thereon in stencil, that is to say the letter area is left clear and all other areas are coated with the reflective material or daylight type paint P with an overcoat of opaque material, as indicated for the letter in FIG. 5. The liner surface 22 would have a contrasting color by comparison with the face 15', and such liner surface 22 could be separate from or a part of the member 14.

The foregoing description has referred to a preferred form of the invention and a modification thereof. These embodiments are given by way of example to provide a clear understanding of the invention, but no limitation is intended thereby except as the invention may be limited by the scope of the appended claims.

What is claimed is:

-1. In a light reflective device: a frame open at one side; a liner removably positionable within said frame and spaced from said open side; a body of transparent material carried by said liner, said body having front and ,rear plane surfaces and the front sur-face being visible from the Open side of said frame; a source of electrical light in said fram-e disposed adjacent an edge of said body to project light into said body, indicia in optical contact with the rear surface of said body and visible through the front surface thereof, said indicia including a layer of daylight fluorescent pigment and a backing of opaque paint to render said fluorescent pigment layer non-transparent; diflusely light reflective means behind said rear surface of said body and in front of said liner, said light reflective means providing areas unobscured by said indicia for viewing from the front surface of said body and exposed to ambient light, said light reflective means behind said body being spaced from the rear surface of said body by said layers of pigment and paint so as not to reflect light from said light source in said frame; and said indicia and light reflective means in said sign alternatively responding to said light source in said frame and ambient light, said indicia being caused to :appear brighter than said light reflective means when said electrical light source in said frame dominates over ambient light, and said light reflective means is caused to appear brighter than said indicia when said light source in said frame is dominated by ambient light.

2. A dual contrast light reflective device comprising: a transparent panel having a front and rear face and 1 areas unobscured by said indicia and visible through the front face of said panel, said liner means having portions abutting the layer of pigment and back-up coating and being obscured from view through the front face of said panel and other portions constituting said unobscured areas comprising a layer of material diffusely reflective to conditions of light passing through the front face of said panel from outside the device, said unobscured area being reflective under conditions of illumination passing through said front face of said panel from outside said device and dominating over internal illumination, and a source of internal illumination adjacent at least one bounding edge of said panel to project its light into said panel and cause said indicia to reflect said light, said indicia at times appearing brighter than said unobscured liner areas when said internal illumination dominates 'over external illumination, and said liner areas at times appearing brighter than said indicia when the external illumination dominates over internal illumination.

8 References Cited by the Examiner UNITED STATES PATENTS 1,364,916 1/21 Carse 40-130 1,654,370 12/ 27 Goetschius 40-134 1,707,965 4/29 Scantlebury 40-130 1,850,319 3/32 Fensom 40-130 1,933,216 10/33 Juhasy 40-130 2,566,458 9/51 Macau 40-130 2,689,917 9/54 Switzer 40-130 2,827,557 3/58 Neugass 40-130 3,027,669 4/62 Hardesty 40-130 EUGENE R. OAPOZIO, Primary Examiner.

JEROME SCHNALL, Examiner. 

2. A DUAL CONTRAST LIGHT REFLECTIVE DEVICE COMPRISING: A TRANSPARENT PANEL HAVING A FRONT AND REAR FACE AND BOUNDING EDGES, INDICIA HAVING A SIDE IN OPTICAL CONTACT WITH THE REAR FACE OF SAID PANEL AND VISIBLE THROUGH THE FRONT FACE THEREOF, SAID INDICIA INCLUDING A LAYER CONTAINING DAYLIGHT FLOURESCENT PIGMENT AND A BACK-UP OPAQUE COATING RENDERING SAID PIGMENT OPAQUE TO THE PASSAGE THERETHROUGH OF LIGHT AND REDIRECTING LIGHT THROUGH THE FRONT FACE OF SAID PANEL, AND SAID INDICIA BEING HIGHLY REFLECTIVE UNDER CONDITIONS OF ILLUMINATION FROM INSIDE THE DEVICE DOMINATING OVER EXTERNAL ILLUMINATION, LINER MEANS ADJACENT SAID REAR FACE OF SAID PANEL AND HAVING AREAS UNOBSCURED BY SAID INDICIA AND VISIBLE THROUGH THE FRONT FACE OF SAID PANEL, SAID LINER MEANS HAVING PORTIONS ABUTTING THE LAYER OF PIGMENT AND BACK-UP COATING AND BEING OBSCURED FROM VIEW THROUGH THE FRONT FACE OF SAID PANEL AND OTHER PORTIONS CONSTITUTING SAID UNOBSCURED AREAS COMPRISING A LAYER OF MATERIAL DIFFUSELY REFLECTIVE TO CONDITIONS OF LIGHT PASSING THROUGH THE FRONT FACE OF SAID PANEL FROM OUTSIDE THE DEVICE, SAID UNOBCURED AREA BEING REFLECTIVE UNDER CONDITIONS OF ILLUMINATION PASSING THROUGH SAID FRONT FACE OF SAID PANEL FROM OUTSIDE SAID DEVICE AND DOMINATING OVER INTERNAL ILLUMINA- 